Connolly Co-authors Article on Density of Galaxies

Assistant Professor of Physics Natalia Connolly was a co-author of an article published in the Sept. 20 issue of The Astrophysical Journal. The article, “The BOSS Emission-Line Lens Survey. II. Investigating Mass-density Profile Evolution in the SLACS+BELLS Strong Gravitational Lens Sample,” presents the results of research into possible ways in which the density in the centers of the biggest galaxies has increased over the last six billion years.

The research was conducted by Adam Bolton and other researchers from the University of Utah, as well as members of Bolton’s team from the Sloan Digital Sky Survey-III (SDSS). Connolly is a member of the SDSS team. A 2.5-meter optical telescope at Apace Point, N.M. and the Hubble Space Telescope were used for the study.

According to Bolton, the article’s principal author, “during the last 6 billion years, the matter that makes up massive elliptical galaxies is getting more concentrated toward the centers of those galaxies. This is evidence that big galaxies are crashing into other big galaxies to make even bigger galaxies.” He said that while “most recent studies have indicated that these massive galaxies primarily grow by eating lots of smaller galaxies,” the evidence presented in this article suggests “that major collisions between massive galaxies are just as important as those many small snacks.”